With the developing of low carbon energy, stricter requirements have been made to energy conservation and emission reduction. New energy automobiles are taken as a strategic direction of the automobile industry development for various countries in the world. Electric automobiles or hybrid automobiles have become one of the future developing directions for automobiles due to having a characteristic of energy conservation and emission reduction. The electric automobiles, however, employ a battery as the power source, since the battery is a core component, a cost of the battery and a ratio of a capacity to a weight of the battery restrict the development of the new energy automobiles. An air conditioning system of the electric automobile is also different from that of an original automotive air conditioning system. For a conventional internal combustion engine automobile, exhaust heat of an internal combustion engine and exhaust gas heat of an engine are used for heating a compartment, however, a power for the electric automobile is mainly from an electrical machine, and there is no exhaust gas heat of the engine that can be used.
In addition, in the conventional internal combustion engine automobile, a blower and a condenser motor are main electric power consuming devices in the automotive air conditioning, while electric power consuming devices in the electric automobile/the hybrid automobile are not only the blower and the condenser motor, for example:
Firstly, there is no engine to drive a compressor, thus the compressor completely relies on the electric power.
Secondly, since there is no engine, there is no exhaust heat of the engine to be used in a heating process, and the heating process also completely relies on the electric power, thus a main issue for the air conditioning of the electric automobile or the hybrid automobile is to improve utilization rate of electric energy.
Thirdly, for poor environmental areas, such as areas where are extremely hot in summer or areas where are extremely cold in winter, to improve the utilization rate of the electric energy is particularly crucial.
In an air conditioning system of an electric automobile in FIG. 8, this system has two main cycles, that is, a refrigerating cycle 1000 and a heating cycle 2000. The air conditioning system of the electric automobile includes two air conditioning case assemblies, that is, a compartment air conditioning case 1010 and a battery module air conditioning case 1020. The compartment air conditioning case 1010 includes a compartment evaporator 1011 and a compartment heater 1012, and the battery module air conditioning case 1020 includes a battery module evaporator 1021 and a battery module heater 1022. During the refrigerating cycle 1000, an operating process of the air conditioning system of the electric automobile is as follows: in a summer working condition, the air conditioning is started; a compressor 1001 starts to work and consumes a certain amount of electric energy to compress a low-temperature and low-pressure gaseous working medium into a high-temperature and high-pressure gaseous working medium. The working medium releases heat when flowing through a condenser 1002, and the heat released by the working medium is absorbed by an ambient air, and the working medium has a phase change and is condensed into a liquid working medium. A temperature and a pressure of the working medium are reduced when the liquid working medium flows through an expansion valve 1003 and/or an expansion valve 1005, the working medium then absorbs heat of air in a compartment and/or a battery when flowing through the compartment evaporator 1011 and/or the battery module evaporator 1021, the working medium has phase change and is evaporated into the gaseous working medium, thus the low-temperature and low-pressure gaseous working medium is compressed into the high-temperature and high-pressure gaseous working medium by the compressor 1011. The above process is repeated again and again. The two evaporators 1011 and 1021 in the air conditioning system may separately operate, and flow passages are controlled through connection and disconnections of two solenoid valves 1004 and 1006.
And during the heating cycle 2000, the operating process of the air conditioning system of the electric automobile is that: in a winter working condition, an electric heater 2003 is energized to heat a working medium in the heating cycle 2000, and meanwhile a water pump 2001 is started to pump the heated working medium to a heater 1012 and/or a heater 1022, the air in the compartment and/or the battery is heated, and flow passages are controlled through connections and disconnections of two solenoid valves 2004 and 2006.
The above air conditioning system, however, still has the following disadvantages.
1. During the refrigerating cycle, a suction temperature of the compressor is substantially equal to vaporization temperatures of outlet ends of the evaporators 1011 and 1021, and a suction pressure of the compressor is substantially equal to vaporization pressures of the outlet ends of the evaporators 1011 and 1021, therefore when the air conditioning system is in a high-temperature area, where is extreme hot, the suction temperature and the suction pressure of the compressor are relatively low, thus a compression efficiency of the compressor is decreased, and also requirements for enough refrigerating capacity cannot be guaranteed.
2. The refrigerating cycle employs the air conditioning system in the conventional automobile to cool the compartment or the battery simultaneously or separately; while the heating cycle employs a high pressure positive temperature coefficient, that is, an electrical heating manner, to cool the compartment or the battery simultaneously or separately. When the electrical heating is employed, the highest efficiency thereof is 100%. Thus, the air conditioning system includes a heating cycle system of the working medium in the heating cycle 2000 besides the refrigerating cycle, that is the air conditioning system has a very complicated structure.
3. And during the heating cycle, the working medium is heated completely by consuming the electric energy in an electrical energy system of the whole automobile, and the air in the compartment and/or the battery exchange heat with relatively hot working medium in a radiator, and then the heated air is delivered to the compartment and/or the battery. There must be heat loss in these heat exchanging process, thus the efficiency of the heating cycle is absolutely less than 1.
4. In addition, during the heating cycle, since the working medium in the heating cycle 2000 has a relatively large specific heat, and a power of the electric heater is limited, the temperature of the working medium in the heating cycle 2000 is slowly increased, and a temperature of the air is also slowly increased, thereby adversely affecting a comfort of passengers.
5. Since a heating device such as the battery has a low temperature when the heating device is just started, and the temperature of the heating unit is slowly increased, thus an operation performance of the heating unit, such as the battery may be adversely affected (for example, a travel mileage may be shortened, or a service life may be shortened).
6. The air conditioning system includes both the refrigerating cycle of the working medium and the heating cycle of the working medium in the heating cycle 2000, thus the number of parts is relatively large, the structure of the air conditioning system is relatively complicated, thus it is difficult to arrange the air conditioning system in the automobile, and a manufacturing cost is relatively high.
Therefore, the automotive air conditioning system needs to be modified into a heat pump type air conditioning system, however, the conventional heat pump type air conditioning generally does not use a micro-channel heat exchanger as an outdoor heat exchanger.